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United States Patent |
5,156,476
|
Ishihara
,   et al.
|
October 20, 1992
|
Paper feed mechanism
Abstract
A paper feed mechanism for feeding fan-fold paper into a printer, a
typewriter, or the like has a drive roller, an idler roller, and a pin
belt trained around the drive and idler rollers and having a series of
pins for engaging in perforations of the fan-fold paper. The fan-fold
paper is guided by first and second paper holders that are angularly
supported on a frame. The first paper roller is of an arcuate shape and
extending along an outer periphery of the drive roller. The first paper
roller is angularly movably supported on the second paper roller. The
second paper roller extends along a straight portion of the pin belt
between the drive and idler rollers.
Inventors:
|
Ishihara; Koichi (Kurume, JP);
Tosa; Takashi (Tosu, JP)
|
Assignee:
|
Matsushita Electric Industrial Co., Ltd. (Osaka, JP)
|
Appl. No.:
|
704252 |
Filed:
|
May 22, 1991 |
Foreign Application Priority Data
Current U.S. Class: |
400/616.2; 226/74 |
Intern'l Class: |
B41J 011/26 |
Field of Search: |
400/616-616.3
226/74,75
352/183
|
References Cited
U.S. Patent Documents
4682904 | Jul., 1987 | Yoshimura et al. | 226/74.
|
4742946 | May., 1988 | Hamamichi et al. | 400/616.
|
4804124 | Feb., 1989 | Hirth | 400/616.
|
4828157 | May., 1989 | Yokoi | 400/616.
|
4836430 | Jun., 1989 | Unuma et al. | 400/616.
|
4836431 | Jun., 1989 | Hirth | 226/74.
|
4952087 | Aug., 1990 | Iwata et al. | 400/616.
|
4989771 | Feb., 1991 | Ferguson | 226/74.
|
Foreign Patent Documents |
0074855 | Apr., 1988 | JP | 226/74.
|
0167150 | Jun., 1989 | JP | 226/74.
|
Primary Examiner: Eickholt; Eugene H.
Attorney, Agent or Firm: Lowe, Price, LeBlanc & Becker
Claims
We claim as our inventions:
1. A paper feed mechanism for feeding fan-fold paper with perforations,
comprising:
first and second rollers spaced from each other, one of said first and
second rollers being drivable to rotate about its own axis, said first and
second rollers having different diameters;
a pin belt trained around only said first and second rollers, said pin belt
having a series of pins for engaging in the perforations of the fan-fold
paper, said pin belt having a straight portion extending between said
first and second rollers;
a first paper holder for holding and guiding the fan-fold paper along said
pin belt, said first paper holder extending along an outer periphery of
one of said first and second rollers which is larger in diameter;
a second paper holder for holding and guiding the fan-fold paper along said
pin belt, said second paper holder extending along said straight portion
of the pin belt; and
a platen for guiding the fan-fold paper to travel therearound, the other of
said first and second rollers which is smaller in diameter being
positioned more closely to said platen than said one of the first and
second rollers.
2. A paper feed mechanism for feeding fan-fold paper with perforations,
comprising:
first and second rollers spaced from each other, one of said first and
second rollers being drivable to rotate about its own axis, said first and
second rollers having different diameters;
a pin belt trained around said first and second rollers, said pin belt
having a series of pins for engaging in the perforations of the fan-fold
paper, said pin belt having a straight portion extending between said
first and second rollers;
a first paper holder for holding and guiding the fan-fold paper along said
pin belt, said first paper holder extending along an outer periphery of
one of said first and second rollers which is larger in diameter; and
a second paper holder for holding and guiding the fan-fold paper along said
pin belt, said second paper holder extending along said straight portion
of the pin belt,
wherein said first paper holder is angularly movably supported on said
second paper holder by a pivot pin.
3. A paper feed mechanism according to claim 1, further including a drive
shaft and a guide shaft spaced from and extending parallel to said drive
shaft, the drivable one of the first and second rollers being fixedly
mounted on said drive shaft, the other of the first and second rollers
being rotatably mounted on said guide shaft, and a frame mounted on said
drive and guide shafts, said second paper holder being angularly movably
supported on said frame by a pivot pin.
4. A paper feed mechanism according to claim 1, further including a platen
spaced from and disposed adjacent to said pin belt, the smaller-diameter
one of the first and second rollers being positioned below a line
interconnecting the center of the larger-diameter one of the first and
second rollers and the center of said platen.
5. A paper feed mechanism according to claim 1, further including a platen
positioned such that a line extending from said second paper holder is
tangential to an outer periphery of the platen.
6. A paper feed mechanism for feeding fan-fold paper with perforations,
comprising:
first and second rollers spaced from each other, one of said first and
second rollers being drivable to rotate about its own axis, said first and
second rollers having different diameters;
a pin belt trained around said first and second rollers, said pin belt
having a series of pins for engaging in the perforations of the fan-fold
paper, said pin belt having a straight portion extending between said
first and second rollers;
a first paper holder for holding and guiding the fan-fold paper along said
pin belt, said first paper holder extending along an outer periphery of
one of said first and second rollers which is larger in diameter;
a second paper holder for holding and guiding the fan-fold paper along said
pin belt, said second paper holder extending along said straight portion
of the pin belt; and
a platen positioned such that a line extending from said second paper
holder is tangential to an outer periphery of the platen,
wherein said first paper holder has an end surface for guiding the fan-fold
paper at a common line tangential to both said platen and the
larger-diameter one of the first and second rollers.
7. A paper feed mechanism for feeding fan-fold paper with perforations,
comprising:
a platen for guiding the fan-fold paper there-around;
a first roller rotatable about a first axis parallel to said platen;
a second roller rotatable about a second axis parallel to said platen, said
second roller being spaced from and greater in diameter than said first
roller and positioned more remotely from said platen than said first
roller;
a pin belt trained around said first and second rollers, said pin belt
having a series of equally-spaced pins for engaging in the perforations of
the fan-fold paper;
a print head for printing the fan-fold paper, said print head being
disposed opposite to said platen in spaced-apart relationship thereto;
a first paper holder for guiding the fan-fold paper, which either has been
printed or is to be printed by said print head, along an outer periphery
of said second roller; and
a second paper holder for guiding the fan-fold paper, which is to be
printed by said print head, along a portion of said pin belt which extends
from said second roller toward said first roller.
8. A paper feed mechanism for feeding fan-fold paper with perforations,
comprising:
a platen for guiding the fan-fold paper there-around;
a first roller rotatable about a first axis parallel to said platen;
a second roller rotatable about a second axis parallel to said platen, said
second roller being spaced from and greater in diameter than said first
roller;
a pin belt trained around said first and second rollers, said pin belt
having a series of equally-spaced pins for engaging in the perforations of
the fan-fold paper;
a print head for printing the fan-fold paper, said print head being
disposed opposite to said platen in spaced-apart relationship thereto;
a first paper holder for guiding the fan-fold paper, which is to be printed
by said print head, along a portion of said pin belt which extends from
said second roller toward said first roller,
wherein said first paper holder is mounted on said second paper holder.
9. A paper feed mechanism for feeding fan-fold paper with perforations,
comprising:
a platen for guiding the fan-fold paper there-around;
a first roller rotatable about a first axis parallel to said platen;
a second roller rotatable about a second axis parallel to said platen, said
second roller being spaced from and greater in diameter than said first
roller;
a pin belt trained around said first and second rollers, said pin belt
having a series of equally-spaced pins for engaging in the perforations of
the fan-fold paper;
a print head for printing the fan-fold paper, said print head being
disposed opposite to said platen in spaced-apart relationship thereto;
a first paper holder for guiding the fan-fold paper, which either has been
printed or is to be printed by said print head, along an outer periphery
of said second roller; and
a second paper holder for guiding the fan-fold paper, which is to be
printed by said print head, along a portion of said pin belt which extends
from said second roller toward said first roller,
wherein said first paper holder is mounted on said second paper holder, and
wherein said first axis is positioned below a line interconnecting the
center of said print head and the center of said platen, and said second
axis is positioned above said line.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a paper feed mechanism for feeding
continuous forms of paper, known as fan-fold paper, on a printer, a
typewriter, or the like.
2. Prior Art
Paper feed mechanisms for continuously feeding fan-fold paper in the form
of a series of joined papers of paper are generally classified into two
categories. The paper feed mechanisms in one of the groups comprise a
pin-feed tractor unit having a set of pins for engaging in perforated
holes in the paper and pulling the paper across the print head of a
printer, a typewriter, or the like. The paper feed mechanisms belonging to
the other class comprise a pin-feed tractor unit which is designed to push
the paper into the printing position in a printer, a typewriter, or the
like.
FIGS. 6 and 7 of the accompanying drawings show one conventional paper feed
mechanism, and FIG. 8 illustrates continuous forms of paper, i.e.,
fan-fold paper. The continuous forms of paper, indicated at 1 in FIG. 8,
have a series of perforations 1a defined in each of their opposite side
edges. In each of FIGS. 6 and 7, the fan-fold paper 1 is held against and
travels around a cylindrical platen 2. The perforations 1a are engaged by
successive pins 12a disposed on the outer peripheral surfaces of pin belts
12. The pin belts 12 are trained around a drive roller 13 which is coupled
to a motor (not shown) and two idle rollers 14 which are rotatably
supported on a frame (not shown). A print head 3 is positioned opposite to
the platen 2 with the fan-fold paper 1 therebetween, for printing the
fan-fold paper 1 as it is successively fed by the paper feed mechanism.
The fan-fold paper 1 is held down against the pin belts 12 by angularly
movable paper holders 15, 16 so that it will not disengage from the pins
12a during operation of the paper feed mechanism.
The paper feed mechanism shown in FIG. 6 is arranged to pull the fan-fold
paper 1 to feed it over the platen 2 across the print head 3. To set the
fan-fold paper 1 in position, it is threaded upwardly between the platen 2
and the print head 3, and, while the paper holders 15, 16 are being turned
upwardly away from the pin belts 12, the perforated holes 1a in the
fan-fold paper 1 are aligned with and fitted over the pins 12a on the pin
belts 12. Then, the paper holders 15 are brought down over the pin belts
12, holding the fan-fold paper 1 against removal. When the pin belts 12
are rotated in the direction indicated by the arrows A by the drive roller
13, the fan-fold paper 1 is pulled by the pin belts 12 in the direction
indicated by the arrows B. The fan-fold paper 1 is now fed along so as to
travel between the platen 2 and the print head 3.
The paper feed mechanism shown in FIG. 7 is arranged to push the fan-fold
paper 1 to feed it under the platen 2 across the print head 3. To set the
fan-fold paper 1 in position, the paper holders 15, 16 are turned upwardly
away from the pin belts 12, and the perforations 12a are aligned with and
fitted over the pins 12a. The paper holders 15, 16 are then turned down
over pin belts 12, holding the fan-fold paper 1 against removal. The
fan-fold paper 1 is taken under the platen 2 and then guided upwardly
between the platen 2 and the print head 3. When the pin belts 12 are
rotated in the direction indicated by the arrows C by the drive roller 13,
the fan-fold paper 1 is pushed by the pin belts 12 in the direction
indicated by the arrows D. The fan-fold paper 1 is now fed along so as to
travel between the platen 2 and the print head 3.
With the conventional structures shown in FIGS. 6 and 7, however, since the
three rollers 13, 14 are used to drive and support the pin belts 12, the
pin belts 12 are relatively long. Therefore, the pin belts 12 tend to
elongate, sag, and vibrate. The vibration of the pint belts 12 causes the
fan-fold paper 1 to move over back and forth. When the fan-fold paper 1
moves over during printing operation, any letters, numerals, or images are
printed on the fan-fold paper 1 by the print head 3 with low quality.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a paper feed mechanism
for feeding fan-fold paper, the paper feed mechanism having relatively
short pin belts that are prevented from sagging and vibrating, thereby
allowing a print head to print the fan-fold paper with high quality.
A paper feed mechanism for feeding fan-fold paper with perforations into a
printer, a typewriter, or the like includes first and second rollers
spaced from each other, one of said first and second rollers being
drivable to rotate about its own axis, said first and second rollers
having different diameters, a pin belt trained around said first and
second rollers, said pin belt having a series of pins for engaging in the
perforations of the fan-fold paper, said pin belt having a straight
portion extending between said first and second rollers, a first paper
holder for holding and guiding the fan-fold paper along said pin belt,
said first paper holder extending along an outer periphery of one of said
first and second rollers which is larger in diameter, and a second paper
holder for holding and guiding the fan-fold paper along said pin belt,
said second paper holder extending along said straight portion of the pin
belt.
The above and other objects, features and advantages of the present
invention will become more apparent from the following description when
taken in conjunction with the accompanying drawings in which a preferred
embodiment of the present invention is shown by way of illustrative
example.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a paper feed mechanism according to the
present invention;
FIGS. 2 and 3 are schematic side elevational views of printers each
incorporating the paper feed mechanism shown in FIG. 1;
FIGS. 4 and 5 are side elevational views of the paper feed mechanism,
showing paper holders opened in different modes;
FIGS. 6 and 7 are schematic side elevational views of printers each
incorporating a conventional paper feed mechanism; and
FIG. 8 is a perspective view of continuous forms of paper, i.e., fan-fold
paper.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows a paper feed mechanism according to the present invention. The
paper feed mechanism is used to feed continuous forms of paper, known as
fan-fold paper, designated by the reference numeral 1 in FIGS. 2 and 3.
While only one paper feed mechanism is shown in FIG. 1, there are actually
two identical paper feed mechanisms which engage opposite side edges of
the fan-fold paper to feed the same.
The fan-fold paper 1 has a succession of equally spaced perforated holes 1a
(FIGS. 2 and 3) defined in each of the opposite side edges thereof. While
the fan-fold paper 1 is fed in a printer, a typewriter, or the like by the
paper feed mechanism, it travels around a cylindrical platen 2 and between
the cylindrical platen 2 and a print head 3 that is positioned opposite to
the platen 2 in spaced-apart relationship. The cylindrical platen 2 and
the print head 3 are of known nature and may be identical to those shown
in FIGS. 6 and 7.
As shown in FIG. 1, the paper feed mechanism has a pin belt 4 having a
series of pins 4a on its outer peripheral surface at the same interval as
the perforations 1a. During operation of the paper feed mechanism, the
pins 4a are inserted successively into and disengage successively from the
perforations 1a. The pin belt 4 is trained around a drive roller 5 and an
idler roller 6 which is smaller in diameter than the drive roller 5. The
drive roller 5 is mounted on a drive shaft 7 which is coupled to a motor
(not shown). The idler roller 6 is rotatably mounted on a guide shaft 8
that is spaced from and extends parallel to the drive shaft 7, the guide
shaft 8 being lower than the shaft 7. The central axis of the idler roller
6, i.e., the guide shaft 8, is positioned below a straight line
interconnecting the central axis of the drive roller 5, i.e., the drive
shaft 7, and the central axis of the platen 2. The central axis of the
idler roller 6 is positioned below a straight line interconnecting the
geometrical center of the print head 3 and the central axis of the platen
2, and the central axis of the drive roller 5 is positioned above the same
straight line.
Paper holders 9, 10 are angularly movably supported on a frame 17 (see
FIGS. 4 and 5) mounted on the shafts 7, 8, the frame 17 being omitted from
illustration in FIG. 1.
More specifically, the paper holder 9 is pivotally supported on the frame
17 by a pivot pin 18 parallel to the frame 17, i.e., perpendicularly to
the shafts 7, 8. The paper holder 9 can be turned between a lying position
(see FIG. 4) in which it lies over the pin belt 4 and a lifted position
(see FIG. 5) in which it is angularly displaced away from the pin belt 4.
The paper holder 9 is normally biased into the lying position under the
resiliency of a spring 11 acting between the frame 17 and the paper holder
9. The paper holder 9 is of a substantially flat shape and extends over a
straight portion of the pin belt 4 above the idler roller 6 and between
the idler roller 6 and the drive roller 5. The paper holder 10 is
angularly movably mounted by pivot pins 19 parallel to the frame 17 on the
upper portion of the paper holder 9 which extends over the drive roller 5.
The paper holder 10 can be turned with respect to the paper holder 9
between a lying position (see FIG. 1) in which the paper holder 10 is held
against the paper holder 9 and a lifted position (see FIG. 4) in which the
paper holder 10 is angularly displaced away from the paper holder 9. The
paper holder 10 is of an arcuate shape and extends partly around the drive
roller 5.
A line extending longitudinally from the paper holder 9 as it is in the
lying position is tangential to the outer peripheral surface of the platen
2. The paper holder 10 has an end surface 10a which, when the paper holder
10 is in the lying position, guides the fan-fold paper 1 at a common line
which is tangential to both the drive roller 5 and the platen 2.
When the paper holder 9 is in the lying position, as shown in FIG. 1, with
the fan-fold paper 1 held therebelow, it guides the fan-fold paper 1 along
the straight portion of the pin belt 4 between the drive roller 5 and the
idler roller 6. When the paper holder 10 is in the lying position as shown
in FIG. 1, with the fan-fold paper 1 held therebelow, it guides the
fan-fold paper 1 partly around the drive roller 5 along its upper outer
peripheral portion.
Operation of the paper feed mechanism according to the present invention
will be described below.
FIGS. 2 and 4 show the paper feed mechanism as it is arranged to pull the
fan-fold paper 1 into the printer, for example, to feed the same
continuously. First, the fan-fold paper 1 is threaded between the platen 2
and the print head 3, and the paper holder 10 is turned upwardly into the
lifted position away from the paper holder 9, as shown in FIG. 4. The
perforations 1a in the fan-fold paper 1 are aligned with and fitted over
those pins 4a which are positioned along the upper outer periphery of the
drive roller 5. Thereafter, the paper holder 10 is turned downwardly into
the lying position against the paper holder 9, thereby holding the
fan-fold paper 1 down against the pin belt 4 as shown in FIG. 2. The
fan-fold paper 1 is now securely retained in the paper feed mechanism
against dislodgement therefrom. Now, the drive roller 5 is rotated by the
drive shaft 7 to rotate the pin belt 4 in the direction indicated by the
arrow E (FIG. 2). The fan-fold paper 1 is pulled by the pins 4a of the pin
belt 4, moving in the direction indicated by the arrow F while passing
between the platen 2 and the print head 3.
FIGS. 3 and 5 show the paper feed mechanism as it is arranged to push the
fan-fold paper 1 into the printer, for example, to feed the same
continuously. First, the paper holder 9 and hence the paper holder 10
supported thereon are brought into the lifted position away from the pin
belt 4, as illustrated in FIG. 5. The perforated holes 1a in the fan-fold
paper 1 are aligned with and fitted over those pins 4a which are
positioned along the upper outer periphery of the drive roller 5 and the
upper straight portion of the pin belt 4. Then, the paper holders 9, 10
are turned downwardly into the lying position to hold the fan-fold paper 1
down against the pin belt 4 so that the fan-fold paper 1 will not be
dislodged from the paper feed mechanism. The drive roller 5 is rotated by
the drive shaft 7 to rotate the pin belt 4 in the direction indicated by
the arrow G (FIG. 3). The fan-fold paper 1 is pushed by the pins 4a of the
pin belt 4, moving in the direction indicated by the arrow H while passing
between the platen 2 and the print head 3.
The paper feed mechanism according to the illustrated embodiment employs
only two rollers, i.e., the drive roller 5 and the idler roller 6.
Therefore, the pin belt 4 trained around these rollers may be shorter than
the pin belt trained around the three rollers of the conventional paper
feed mechanism. The pin belt 4 is thus subject to less elongation,
sagging, vibration, and unwanted lateral movement. Accordingly, the
fan-fold paper 1 fed by the paper feed mechanism can be printed with high
quality.
Although a certain preferred embodiment has been shown and described, it
should be understood that many changes and modifications may be made
therein without departing from the scope of the appended claims.
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